School of Industrial Fisheries, Cochin University of Science & Technology, Cochin, India.
J Fish Biol. 2020 Jan;96(1):130-139. doi: 10.1111/jfb.14194. Epub 2019 Nov 27.
The feeding strategy, overlap and trophic interactions of four demersal catfishes inhabiting Cochin Estuary, Arius maculatus (n = 67), A. subrostratus (n = 63), A. arius (n = 21) and Mystus gulio (n = 69) were investigated through gut-content analyses. The indices of relative importance revealed that the prey items in their stomachs were dominated by crustaceans except in A. arius where molluscs constituted the major prey item. The highest diet and niche breadth values (3.93, 0.36 respectively) were recorded in A. subrostratus, while the lowest was recorded in A. arius (2.64, 0.23 respectively). Pianka's overlap, calculated through null models constructed by Ecosim 7.0, revealed significant niche overlap between A. maculatus and A. subrostratus (O-0.91, P < 0.001), between A. maculatus and M. gulio (O-0.72, P < 0.05) and between A. subrostratus and M.gulio (O-0.64 P < 0.05). However, no overlap was recorded between A. arius and other species. The trophic niche breadth along with prey specific abundance confirmed that these fishes are highly specific feeders. The present results on trophic level status indicate that these catfishes are mid-level carnivores that can be considered as moderate benthic mesopredators and are specialist feeders unlike most catfishes.
通过对科钦河口栖息的四种底栖鲶鱼（Arius maculatus（n=67）、A. subrostratus（n=63）、A. arius（n=21）和 Mystus gulio（n=69））的摄食策略、重叠和营养相互作用进行了研究。通过肠道内容物分析，发现除了 A. arius 外，甲壳类动物是这些鱼胃中主要的食物来源，其胃中的食物主要由甲壳类动物组成。在 A. subrostratus 中，饮食和生态位宽度指数最高（分别为 3.93 和 0.36），而在 A. arius 中则记录到最低值（分别为 2.64 和 0.23）。通过 Ecosim 7.0 构建的零模型计算的 Pianka 重叠度表明，A. maculatus 和 A. subrostratus（O-0.91，P<0.001）、A. maculatus 和 M. gulio（O-0.72，P<0.05）以及 A. subrostratus 和 M. gulio（O-0.64，P<0.05）之间存在显著的生态位重叠。然而，A. arius 与其他物种之间没有重叠。营养生态位宽度和特定猎物丰度的结果证实，这些鱼类是高度特异的摄食者。这些关于营养层次地位的结果表明，这些鲶鱼是中级肉食性动物，可以被认为是适度的底栖中型捕食者，与大多数鲶鱼不同，它们是专门的食者。
